To expedite the identification of potential Cryptosporidium chemotherapeutic and immunotherapeutic targets and to provide nucleic acid sequence information that will allow immediate isolation of the corresponding genes a focused, short-term project whose goal is the determination and rapid public distribution of 5,000 C. parvum gene sequence tags (GST's 300-600 bp of single-pass nucleotide sequence from random genomic DNA clones) is proposed. The specific aims of the application are: (1) Construct and characterize randomly-sheared genomic DNA libraries from the Iowa isolate of C. parvum, (2) Determine 5,000 C. parvum GST's by single-pass automated fluorescent sequencing of both ends of 2,500 random genomic DNA clones, and (3) Deposit GST sequences as they are completed in the public GenBank genome survey sequence database (dbGSS) and establish an Internet site devoted to distribution and analyses of the C. parvum GST's determined in this investigation.